If it was 'the Bolshevik', it would be understandable ('Used to make a generalized reference to something rather than identifying a particular instance,' the third sense here: https://www.lexico.com/en/definition/the). And yet, it's plural. The similar goes for names of nationalities. Most examples in the Lexico entry for 'Russian' that use the plural form go with 'the' (https://www.lexico.com/en/definition/russian). Some, on the other hand, do not (for instance, 'It was Russians who first built up a caviar industry on Iranian shores.'). Please explain.
When talking about a fully specified group of people or things we can use "the" to mean that fully specified group.
The lions come down to the waterhole at night
The English enjoy tea
The punks would wear ripped t-shirts.
The Bolshovicks were a political party that gain control of Russia following the October revolution.
And so on.